1. Field of the Invention
This invention concerns a method for defluorinating a perfluoroalkene to the corresponding more highly unsaturated fluorocarbon.
2. References
U.S. Pat. No. 4,377,717, issued to Anello, et al., on Mar. 22, 1983, discloses dimerization of hexafluoropropene to perfluoro-2-methylpentene-2 by heating at elevated temperatures in the presence of activated carbon.
Chambers, et al., J.C.S. Perkin I, 1064 to 1067 (1981), and Chem. Comm., 475 and 476 (1978), describe defluorination of perfluorinated alkenes over platinum, iron, and cesium fluoride at elevated temperatures to give perfluorinated dienes and other products.
U.S. Pat. No. 2,709,182, issued to Farlow on May 24, 1955, discloses preparation of tetrafluoroethylene by a process wherein a fluorocarbon of at least three carbons and of a melting point no higher than 25.degree. C. is pyrolyzed by heating at a temperature of at least 1500.degree. C. Pyrolysis by passing the fluorocarbon between carbon electrodes is specifically disclosed.
U.S. Pat. No. 23,425, issued to Harmon on Oct. 30, 1951, discloses a process for making completely halogenated polyfluorohydrocarbons comprising heating at a temperature of at least 125.degree. C. a completely halogenated ethylene of the formula CX.sub.2 .dbd.CX.sub.2, wherein X is halogen and at least 2 of the halogens are fluorine. The use of activated charcoal in the process is disclosed.
Ohsaka, et al., Chem. Abstracts 94, 191660 (1981) (Ger. Offen. No. 3,027,229) disclose oligomerization of hexafluoropropene over an alkali fluoride on carbon or NiO catalyst. Specifically disclosed is the oligomerization of C.sub.3 F.sub.6 over KF on carbon at 200.degree. C. to give a mixture of dimer, trimer, and C.sub.9 F.sub.16.
Baciocchi, in "The Chemistry of Halides, Pseudo-Halides and Azides", Patai and Rappoport editors, John Wiley & Sons, New York, 1983, Chapter 5, pages 161 to 201, has reviewed 1,2-dehalogenations and related reactions.